High-frequency (HF) surgery, of which argon plasma coagulation is a subset, has been used for many years, both in human medicine and in veterinary medicine, to coagulate and/or cut biological tissue. Suitable electrosurgical instruments are used to pass high-frequency current through the tissue to be treated, so that this tissue changes as a result of protein coagulation and dehydration. Vessels can be sealed and bleeding stopped through this coagulation process. A cutting process that follows the coagulation process then enables full separation of tissue that has already coagulated.
Argon plasma coagulation enables a non-contact coagulation of tissue and serves for effective haemostasis and devitalization of tissue. In this type of coagulation, inert working gas, for example argon, is passed via gas supply devices from an argon plasma coagulation instrument to the tissue to be treated. With the help of the working gas, a “plasma jet” can be generated between an electrode at a distal end of the gas supply device, such as a probe, and the tissue. The HF current can then be applied to the tissue to be treated without the electrosurgical instrument coming into contact with the tissue. This, therefore, avoids adherence of the tissue to the instrument.
An undesirable side effect of plasma coagulation, in particular argon plasma coagulation, is the carbonization of the tissue that is seen in virtually all electrosurgical applications. Plasma coagulation is accompanied by a chemically incomplete combustion of the biological tissue which results in carbonization of the tissue to a substantial degree and to the formation of carbon black and plume formation. These disadvantages are seen with argon plasma coagulation to a lesser degree than with laser surgery procedures, but carbonization results, and is accompanied by increased tissue inflammation and increased post-operative problems. The use of higher power and longer application times in argon plasma surgery leads to significant carbonization and therefore emission of carbon black and plumes that are harmful to health and have a strong odor. This necessitates expensive and complicated extraction devices and cleaning of the operating room. A further disadvantage of plasma coagulation is that relatively inhomogeneous tissue damage is seen, caused by the concentrated development of current paths of the noble gas plasma. This produces depressions on the tissue surface, which are carbonized to a greater degree at higher power levels and longer application times than the rest of the tissue surface.